1,478 research outputs found

    VLTI/AMBER spectro-interferometry of the late-type supergiants V766 Cen (=HR 5171 A), sigma Oph, BM Sco, and HD 206859

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    We add four warmer late-type supergiants to our previous spectro-interferometric studies of red giants and supergiants. V766 Cen (=HR 5171 A) is found to be a high-luminosity log(L/L_sun)=5.8+-0.4 source of Teff 4290+-760 K and radius 1490+-540 Rsun located close to both the Hayashi and Eddington limits; this source is consistent with a 40 Msun evolutionary track without rotation and current mass 27-36 Msun. It exhibits NaI in emission arising from a shell of radius 1.5 Rphot and a photocenter displacement of about 0.1 Rphot. V766 Cen shows strong extended molecular (CO) layers and a dusty circumstellar background component. This suggest an optically thick pseudo-photosphere at about 1.5 Rphot at the onset of the wind. V766 Cen is a red supergiant located close to the Hayashi limit instead of a yellow hypergiant already evolving back toward warmer Teff as previously discussed. The stars sigma Oph, BM Sco, and HD 206859 are found to have lower luminosities of about log(L/Lsun)=3.4-3.5 and Teff of 3900-5300 K, corresponding to 5-9 Msun tracks. They do not show extended molecular layers as observed for higher luminosity red supergiants of our sample. BM Sco shows an unusually strong contribution by an over-resolved circumstellar dust component. These stars are more likely high-mass red giants instead of red supergiants. This leaves us with an unsampled locus in the HR diagram corresponding to luminosities log(L/Lsun)~3.8-4.8 or masses 10-13 Msun, possibly corresponding to the mass region where stars explode as type II-P supernovae during the RSG stage. Our previously found relation of increasing strength of extended molecular layers with increasing luminosities is now confirmed to extend to double our previous luminosities and up to the Eddington limit. This might further point to steadily increasing radiative winds with increasing luminosity. [Abridged]Comment: 16 pages, 14 figures, accepted for publication in Astronomy and Astrophysics (A&A

    Tunable Low Density Palladium Nanowire Foams

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    Nanostructured palladium foams offer exciting potential for applications in diverse fields such as catalyst, fuel cell, and particularly hydrogen storage technologies. We have fabricated palladium nanowire foams using a cross-linking and freeze-drying technique. These foams have a tunable density down to 0.1% of the bulk, and a surface area to volume ratio of up to 1,540,000:1. They exhibit highly attractive characteristics for hydrogen storage, in terms of loading capacity, rate of absorption and heat of absorption. The hydrogen absorption/desorption process is hysteretic in nature, accompanied by substantial lattice expansion/contraction as the foam converts between Pd and PdHx.Comment: 17 pages, 4 figure

    Adaptive Control Optimization of Cutting Parameters for High Quality Machining Operations Based on Neural Networks and Search Algorithms

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    This book chapter presents an Adaptive Control with Optimization (ACO) system for optimising a multi-objective function based on material removal rate, quality loss function related to surface roughness, and cutting-tool life subjected to surface roughness specifications constraint

    Study of a Solution with COTS for the LHCb Calorimeter Upgrade

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    AbstractWe present a solution made out of Components Out of Shelf (COTS) for the analog processing of the signal of the LHCb calorimeters in the framework of the foreseen upgrade of the detector. The present proposal is based on the current functional solution, yet, to meet the stringent noise requirements, a number of modifications are proposed. Preliminary results on the prototype boards show promising results

    Monitorización con vídeo-EEG y ECG simultáneo para el diagnóstico diferencial de trastornos de conciencia transitorios. A propósito de un caso

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    We present the case of a 36 year-old woman, with history of transient consciousness disorders with vegetative state, interpreted as epileptic crises and treated with valproate for two years. After nine asymptomatic years, they reappeared associated with migraine, vomiting and some generalized convulsions. Electroencephalogram and cerebral magnetic resonance turned out normal, and treatment with zonisamide was started, without beneficial results. Later cardiological studies objectified a blockage of the left branch that coincided with dizziness. The study was completed with Video-EGG monitoring, where there was an episode that showed temporary right epileptiform activity, with a diagnosis established of focal epilepsy of unknown cause. At present, she remains asymptomatic with oxycarbazepine

    Dietary Vitamin D Intake and Muscle Mass in Older Women. Results from a Cross-Sectional Analysis of the Epidos Study

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    Objectives: Vitamin D intake may prevent physical performance decline through prevention of muscle mass loss. Our objective was to determine whether low dietary intakes were associated with low muscle mass (MM). Design and participants: Cross-sectional analysis of 1989 community-dwelling women (mean age 80.5 +/- 3.8years) from the EPIDemiologie de l\u27OSteoporose (EPIDOS) study were assessed at baseline. Measurements: Low intakes of vitamin D (<70 mu g/week) were estimated from the weekly dietary vitamin D intakes (self-administered food frequency questionnaire). Low MM was defined according to the appendicular skeletal muscle mass index assessed using Dual Energy X-ray Absorptiometry, divided by square height of less than 5.45 kg/m(2). Usual gait speed defined physical performance. Age, sun exposure, co-morbidities, education level, living arrangements, recreational physical activity, dietary protein and calcium intakes, bone mineral density, handgrip strength, and body mass index were considered as potential confounders. Multivariate logistic regression analyses assessed the association between low vitamin D intakes and low MM. Results: Two-hundred and nine (10.5%) women with low MM were compared to 1,780 women with normal MM. In final model, obesity/overweight (Adjusted Odds Ratios, aOR=0.09; 95%CI [0.05-0.17]), malnutrition (aOR=3.90; 95%CI [2.74-5.54]) and low handgrip strength (aOR=2.33; 95%CI [1.44-3.77]; p<0.001) were statistically associated with a low MM status. Conclusion: No association with low MM has been reported regarding low dietary intakes of vitamin D

    Integrated test environment for a part of the LHCb calorimeter - TWEPP09

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    An integrated test environment for the data acquisition electronics of the Scintillator Pad Detector (SPD) from the calorimeter of the LHCb experiment is presented. It allows to test separately every single board or to perform global system tests, while being able to emulate every part of the system and debug it. This environment is foreseen to test the production of spare electronic boards and help the maintenance of the SPD electronics along the life of the detector. The heart of the system is an Altera Stratix II FPGA while the main board can be controlled over USB, Ethernet or WiFi

    Influencia de los métodos de conservación en las actividades enzimáticas de suelos forestales mediterráneos

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    Soil storage method may alter enzymatic activity being storage conditions of the soil samples prior to analysis decisive for the results. Studies made on freshly collected soils are generally preferred. However it is always not possible due to practical reasons since for example sampling is often restricted to short period of the year or because a great quantity of microbiological analyses must be made on time and by few people. On this context, soil storage methods are needed, being cold at 4°C the most widely used although sometimes alternative storage methods are also utilized. The aim of this study is to evaluate the effect of two alternative storage methods of soil samples (freezing at –20°C and air drying conservation methods) in comparison to cold at 4°C on the enzymatic activities (dehydrogenase, phosphatase, β-glucosidase and urease soil enzymes). Samples of two forest ecosystems (pine and holm oak forest stand) were taken in two different season of the year (winter and spring 2009). Results showed that enzymatic activities differed when freezing or air drying conservation methods were used in comparison with cold soil samples. Generally, alternative soil storage methods presented lower enzymatic activity than cold at 4°C. However, these changes depend on season and sampling location.El método de conservación del suelo utilizado puede alterar la actividad enzimática, siendo decisivas para los resultados, las condiciones de conservación previas a los análisis. Para los estudios es preferible realizar los análisis en muestras frescas y recién cogidas. Sin embargo, esto no es siempre posible por razones prácticas ya que las muestras se tienen que recoger en un corto periodo del año o porque los análisis los debe hacer poca gente y siempre en un determinado tiempo. En este contexto, se necesita un método de conservación, siendo el mantenimiento en el frigorífico a 4°C el método más usado, aunque existen otros métodos alternativos. El objetivo de este trabajo es el de evaluar el efecto de dos métodos alternativos de conservación (congelado a –20°C y secado a temperatura ambiente) sobre las actividades enzimáticas (deshidrogenasa, fosfatasa, β-glucosidasa y ureasa), en comparación con el mantenido en el frigorífico a 4°C. Las muestras se obtuvieron de dos zonas forestales diferentes (pinar y encinar) y en dos épocas distintas (primavera y verano de 2009). Los resultados mostraron diferencias en las actividades enzimáticas cuando se usó el congelado o secado al aire de las muestras de suelo en comparación con el mantenimiento en el frigorífico. De forma general, los métodos de conservación alternativos mostraron una menor actividad enzimática en las muestras de suelo analizadas. Sin embargo, estos cambios dependen de la época del año y la zona de muestreo

    Sarcopenia and cognitive impairment in elderly women: results from the EPIDOS cohort

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    BACKGROUND: common pathophysiological pathways are shared between age-related body composition changes and cognitive impairment. OBJECTIVE: evaluate whether current operative sarcopenia definitions are associated with cognition in community-dwelling older women. DESIGN: cross-sectional analyses. SUBJECTS: a total of 3,025 women aged 75 years and older. MEASUREMENTS: body composition (assessed by dual energy X-ray absorptiometry) and cognition (measured by short portable mental status questionnaire) were obtained in all participants. Multivariate logistic regression models assessed the association of six operative definitions of sarcopenia with cognitive impairment. Gait speed (GS, measured over a 6-meter track at usual pace) and handgrip strength (HG, measured by a hand-held dynamometer) were considered additional factors of interest. RESULTS: a total of 492 (16.3%) women were cognitively impaired. The prevalence of sarcopenia ranged from 3.3 to 18.8%. No sarcopenia definition was associated with cognitive impairment after controlling for potential confounders. To proof consistency, the analyses were performed using GS and HG, two well-established predictors of cognitive impairment. Low GS [odds ratio (OR) 2.42, 95% confidence interval (CI) 1.72-3.40] and low HG (OR: 1.81, 95% CI: 1.33-2.46) were associated with cognitive impairment. CONCLUSION: no significant association was evidenced between different operative sarcopenia definitions and cognitive impairment. The study suggests that the association between physical performance and cognitive impairment in not mediated by sarcopenia
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